Really? I got that one rather quickly. Get between 21 and 26 on 2 more places then your opponent. Numeric cards go in the order you place them or the suit, queens change order and suit, kings double whatever you put them on, jacks take whatever you put them on, and Jokers take away all duplicate cards except the one it is played on. It's essentially Blackjack on meth.
Edit: To win easily, use only 6's, 7's, 8's, 9's, 10's, and kings. If all you have is Caravan Deck, also add 2 jacks and queens, and you should be fine. I usually win quickly by playing 10, then 6, then king on 10, or 9 then 8 then king on 9, or anything like that that adds to a number in between 21 and 26. And you can play face cards (aces don't count) on your opponent, turn their 26 to 36, or 16, whatever.